Our new paper introducing the concept of "programmable self-lokcing origami mechamical metamaterials" is published in high-end journal Advanced Materials. The research shows that the non-flat-foldable origami provides a new platform to achieve stiffness programmability via its intrinsic self-locking and reconfiguration capabilities.
Developing mechanical metamaterials with programmable properties is an emerging topic receiving wide attentions. While the programmability mainly originates from structural multistability in previous designed metamaterials, here it is shown that the non-flat-foldable origami provides a new platform to achieve programmability via its intrinsic self-locking and reconfiguration capabilities. Working with the single-collinear (SC) degree-4 vertex origami tessellation, it is found that each unit cell can self-lock at a non-flat configuration and therefore possesses wide design space to program its foldability and relative density.
Experiments and numerical analyses are combined to demonstrate that by switching the deformation modes of the constituent cell from pre-locking folding to post-locking pressing, its stiffness experiences a sudden jump, implying a limiting-stopper effect. Such stiffness jump is generalized to multi-segment piecewise stiffness profile in a multi-layer model. Furthermore, it is revealed that via strategically switching the constituent cells’ deformation modes through passive or active means, the n-layer metamaterial’s stiffness is controllable among 2n target stiffness values.
Additionally, the piecewise stiffness can also trigger bistable responses dynamically under harmonic excitations, highlighting the metamaterial’s rich dynamic performance. These unique characteristics of self-locking origami present new paths for creating programmable mechanical metamaterials with in-situ controllable mechanical properties.